Device for truing and dressing grinding-wheels



E. R. CONNERS.

DEVICE FOR TR-U'ING AND DRESSING GRINDING WHEELS.

APPLICATION FILED MAR. I8. I920.

' Patented Nov. 1, 1921.

2- SHEETS-SHEET I.

E. R. CONNERS.

DEVICE FOR TRUING AND DRESSING GRIN-DING WHEELS. APPLICATION FILED MAR.18. 1920.

1,395,392. Patented Nov. 1, 1921.

2 SHEETSSHEET 2.

UNITED STATES PATENT OFFICE.

EDWARIQ R. CONNERS, OF CINCINNATI, OHIO, ASSIGNOR TO THE PRECISION TRUING MACHINE AND 'ICCL COMPANY, OF CINCINNATI, OHIO, A CORPORA TION OF OHIO.

Specification of Letters Patent.

Patented N or. 1, 1921.

Application filed March 18, 1920. Serial No, 366,970.

To allwhom it may concern:

Be it known that I, EDWARD R. CONNERS, a citizen of the United States, residing at *Cincinnati, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvements in Devices for .Truing and Dressing Grinding-\Vheels, of

which the following is a specification.

My invention relates to devices for truing and dressing grinding or polishing wheels, such as emery wheels, employed in grinding or polishing polishing the surfaces of metal in precision grinding. A usual means heretofore employed in truing and dressing operations on grinding wheels has been a diamond tool comprising a diamond made to contact the grinding surface of the grinding wheel, but diamonds have become very scarce and very expensive, and practically only the poorer grades of diamonds suitable for the purpose have been at all obtainable.

My present invention is an improvement on the invention shown, described and claimed in my copending application for devices for truing and dressing grinding wheels, filed November 2, 1917, Serial No. 199,889.

It is the object of my invention to provide novel means whereby to dispense with the use of diamonds for truing or dressing operations. It is the further object of my invention to provide a rotatable abrading part so positioned that its axis of rotation is pre- HS sented toward the grinding wheel with which it is to coact for the purpose of truing or dressing; further, to provide a r0- tatable abrading part and meanswhereby to position the same with relation to the grind- 0 ing wheel upon which it acts. so that the ro tatable abrading part makes end-contact, preferably with a substantially conical abrading face, with the grinding surface of the grinding wheel; and further. to provide 5 a. rotatable abrading part for the purpose mentioned which has an end contact-face surrounding a'center space which is coincident with the axis of rotation of the rotatable abrading part. B It is the object of my invention, further, to provide a rotary abrading part, preferably of materially less diameter than the machinery for grinding or diameter of the grinding wheel, and having an axis of rotation presented toward the grinding wheel to be trued, and acting with a swirling abrading motion on the rotating grinding wheel for truing and dressing the same; further, to provide a rotary abrading part for truing and dressing the grinding wheel, the said rotary abrading part arranged for end-contact at one side of its axis of rotation with the grinding wheel; and. further, to provide of the character last mentioned which has an end abrading surface surrounding and spaced from its axis of rotation.

It is the object of my invention, tn ther.

to provide novel means for 56361 53111 an E abrading part or pencil in position for rotary motion, further to provide an electric motor for the same on the support of the abrading pencil. and a flexible driving connection between the armature-shaftof the motor and said rotary abrading pencil. and, further. to provide novel means for adjusting the position of the abrading pencil.

The invention will be further readily understood from the following description and claims, and from the drawings, in which latter:

Figure 1 is a plan view of my improved device applied to a grinding machine having a reciprocating carriage for the grinding wheel.

Fig. 2 is an end view broken away for better illustration of parts.

Fig. 3 is a plan view of my improved device applied to a grinding machine having a reciprocating carriage for the work.

Fig. 4 is an end view of the same partly broken away.

Fig. 5 is an enlarged plan view of my improved device. shown in connection with a grinding wheel to be trued or dressed. the latter partly broken away.

Fig. 6 is a side elevation of my improved device, showing the same mounted for truing and dressing a grinding wheel, partly broken away, and partly in cross-section on the line 6-6 of Fig.

Fig. 7 is an axial section of a detail of the same. taken on the line 7- of Fig. 5.

Fig. 8 i an axial section of my improved device taken in the line 8-8 of Fig. 6.

of the same partly a rotarv abrading part V Fig. 8; and,

Fig. 9 is a cross-sectional detail of the same, taken in theplane of the line 9-9 of Fig. 1s a detail in axial section, taken in the plane of the line 10-10 of Fig. 8.

My invention is applicable to machines employing a grinding wheel carriage, or a work-carriage, the former being a machine. in which the grinding wheel is caused to have movement in reverse directions along the work being ground, and the latter being a machine in which the work is caused to have movement in reverse directions lengthwise of the axis of rotation of the grinding wheel.

My invention is exemplified as applied to a machine of the former type in Figs. 1 and 2, and to a machine of the latter type in Fi s. 3 and 4.

eferrin'g to Figs. 1 and 2, 11 represents the machine frame, which has thereon a head-stock 12 comprising a head-center 13, and a tail-stock 14 comprising a tail-center 15, suitable well-known means being provided for causing approach or recession between the head-stock and tail-stock according to the length of work, and for moving the tail-center axially for supporting the piece of work. The work is represented as a heavy shaft 16 between said centers. Suitable means are provided for clamping the work to the head-spindle on which the head-center is located, as by a clamp 17 extending from the face-plate 18, fast on the head-spindle. The head-spindle is rotated by a suitable belt passing about a step pulley 19, fast on the head-spindle.

The frame has guide-ways 21, 22, thereon, along which a carriage 23 is arranged to slide lengthwise of the axes of the head and tail-spindles. The carriage has thereon a shaft 26 arranged to be suitably driven, as by a belt received about a pulley 27 fast on said shaft. the shaft also having releasably clamped fast thereon, a grinding wheel 28 which during the grinding operation moves with the carriage, the periphery ing wheel in the present instance coacting with the surface of the rotating work for grinding or polishing the latter. Suitable means are provided for the movement of the carriage lengthwise of the work, exemplifie d as comprising a screw-rod 29, journaled in suitable hearings on the frame and having threaded connection with the carriage by means of a nut 30 fast on the carriage.

The screw-rod is arranged to be rotated in opposite directions by a shaft 33 having gears 34. normally loose thereon, a clutchcollar 36 having suitable spline and key connection with said shaft. The clutchcollar is located between said gears, the said gears and said clutch-collar having the coacting teeth of clutches 37, 38. thereon.

Gears 41, 42, are fixed to said screw-rod.

of the grind rotates in the opposite direction, whereby the carriageis arranged to be moved lengthwise of the work-support in opposite directions.

Means are provided for automatically reversing the "direction of movement of the carriage which is accomplished, for instance, by providing the carriage with a tappet-lug 45 arranged to engage tappets 46, 47, respectively adjustably secured to a tappet-bar 48, slidable in bearings 49 on the frame. The adjustments maybe made by reaching through the front of the machine-frame, which may be open. A socket-piece 51 is on the tappet-bar and has a finger 52 extending therefrom. The finger is pressed outwardly by a spring 53 in the socket of the socket-piece against a slide-bar 54.

A fork 55 is fixed to a rock-shaft 56, and is received in an annular groove 57 in the clutch-collar 36. The slide-bar is articulated with a tail-piece 59 of the fork at 58. The slide-bar is provided with oppositely inclined faces 61 and 62, with which the finger coacts to push the slide-bar lengthwise in its bearing 63, when the finger is moved off the apex-face 64 of the slide-bar into engagement with either inclined face by the tappet-bar, the spring pressing the finger along the inclined face for imparting a quick endwise movement to the slide-bar and a quick engagement and disengagement of the respective clutches.

WVhen the carriage moves the tappet-bar in one direction, the clutch 37 willbecome disengaged and the clutch 38 engaged, whereas, when the tappet-bar moves in the opposite direction, a reverse relation in the clutches will take place. Stoppage of movement of the carriage is accomplished by means of a hand-lever 65 fast on the rock-shaft 56, by means of which the clutch-collar is'apositioned for disengaging both clutches, ill'l which relation the finger 52 rests on the flattened apex 64 of the slide-bar.

It is necessary in order to obtain continuously true, accurate and desirable grinding.

that the grinding wheel be'maintained in proper grinding condition. The grinding wheel may in course of operation become out of true, that is to say, its periphery or grinding surface will no longer be a perfect cylinder, or the grinding surfacemay in whoh pr in part become polished or substantialls inactive for grinding tween the wheel may trued or dressed condition, I provide a rotary truing or dressing abrading part, preferably of a texture much harder than the texture of the grinding wheel to be trued or dressed, and provide means for rotating said rotary abrading part preferably at a high rate of speed, and preferably so that the rotary abrading part makes substantial end contact with the grinding surface of the grinding wheel, with a swirling motion,

whereby to true and dress the grinding sur-- face and extract the grinding offal from the cavities or pores of the grinding surface, in order to maintain the grinding surface sharp for eflicient grinding. This swirling motion acts abradingly on the grinding surface preferably in a direction during at least part of its contacting action which is opposite to the direction in which the rinding u surface is moving during the grinding operation.

I prefer further that the rotary abrading part shall have a bore coincident with its axis of rotation so that the rotary abrading part at and adjacent to its axis of rotation shall be free of contact with the grinding wheel. I further prefer that the axis of rotation of the abrading wheel, if extended through the circle of the cylinder, formed by the abrading surface of the grinding wheel, shall be a chord to the circle of said cylinder, or that the projection of said axis of rotation with relation to the grinding surface shall be such that the end contact between the rotary abrading part and said grinding surface shall be at one side only of said axis of rotation, whereby the endcontact of the rotary abrading part with said grinding surface shall be by a substantially frusto-conical end of said rotary abrading part.

I further provide means whereby relative movement lengthwise of the axis of the grinding wheel takes place between the rotary abrading part and the grinding wheel during the truing or dressing operation, and I preferably provide means, which may be employed if desired, whereby the grinding be dressed during the grinding operation.

Referring again to Figs. 1 and 2, means are provided for adjusting the distance begrinding wheel and the work, exemplified as accomplished by mounting the bearings of the shaft of the grinding wheel on a slide 66 adjustable crosswise of the carriage on guides 67, as by means of an adjusting screw 68, journaled to the carriage, and having threaded connection with the slide by means of a nut 69 fixed to the slide. A clamp-bolt 70 secures the parts in adjusted positions.

Exemplifying my improved device as applied to a grinding machine having a workcarriage, and referring to Figs. 3 and 4,

parts are shown similar to Figs. 1 and 2, with the difference that the work is mounted on a carriage so as to move lengthwise in opposite directions with relation to the grinding wheel, which is stationarily located, but having adjustment toward and from the work by being mounted on a slide to move transversely to the direction of movement of the work-carriage. In this exemplification the parts are designated by reference numerals, similar to the numerals applied to the parts in Figs. 1 and 2, but raised to the series 100, the screw having connection with the work-carriage for moving the carriage lengthwise to the axis of rotation of the grinding wheel, and the tappet-bar being operated by the work-carriage.

The rotary abrading part of my improved device is designated by the numeral and is represented as a hollow stub or pencil of abrading material, which coacts with the grinding surface of the grinding wheel.

The abrading pencil is shown releasably secured to a shaft 76, which is journaled in bearings 71, 72, of a support 73. (See Figs; 5, 6, 7, and 8.) The bearings are shown at anti-friction bearings, arranged for preventing end-movements or vibrations of the shaft 76. These bearings are shown as radial and end-thrust ball-bearings, and are shown located in a barrel 74-of said support.

The shaft 76 is provided with a chuck 77 for securing the abrading'pencil to the shaft, preferably so that the axis of the abrading pencil is coincident with the axis of rotation of the shaft. The chuck is exemplified as comprising a socket 78, in which the inner end of the abrading pencil is received. The inner face of the socket is taperin or frustoconical to form a wedge wall. plurality of wedge-pieces 79 are received in the socket between the pencil and said wedge-wall and are normally spaced apart by the spaces 80.

A cap 81 is internally threaded and received over the threaded outer wall of the socket, and has an inwardly extending annular flange 82 arranged, when the cap is screwed upon the threaded outer end of the shaft, to move the wedge pieces along the wedge-wall of the socket, for clamping the abrading pencil centrally on the shaft. The shaft may be provided with an enlargement 83. The enlargement and the cap may be provided with suitable means for insuring their relative turning when clamping or unclamping an abrading by providing the enlargement with suitable peripheral holes in which a suitable pin may be received, and providing the cap with a knurled surface, by means of which it ma be screwed on and off of the end of the shaft.

The support 73 is adjustably secured to the work-support, as by providing the support with a stem 87 projecting therefrom, and

pencil in place, as

preferably parallel with the bearing-barrel shaft for the abrading pencil, the wall of the '74 of the support. The stem is adjustably secured to a bracket 84, extending from the barrel. and may extend either forwardly or rearwardly of said bracket, depending on the position in which it is desired to place the abrading pencil with relation to the work-support. The bracket 84 is arranged to be clamped to the stem by means of a setbolt 85. p

The stem is arranged to be received in a suitable aperture 88, exemplified as in a lug 89 on the tail-stock 14, in Figs. 1, 2, and 5, and in a lug 189 in the tail-stock 114, in Figs. 3 and 4, the stem being arranged to be clamped in adjusted positions in its bear: ing, by means of a set-bolt 90, in Figs. 1, 2 and 5, and by a set-bolt 190 in Figs. 3 and 4. The lug has a bearing-ring 91 about the tailcenter 15, and may be adjusted about the axis of said tail-center for presenting the pencil at different angles to the work, and be secured in adjusted positions on the tail-center by a set-bolt 92' The abrading pencil may be swung about the axis of the stern, and about the axis of the tai1-center and moved lengthwise of its own axis in adjusting the same.

A protecting washer 93 is received between the end of the bearing-barrel and the enlargement on the shaft, to prevent dust and dirt getting into the bearings for the shaft 76.

The grinding wheel is instanced as rotating in the direction of the arrow 1), and the work as rotating in the direction of the arrow 0.

I The abrading pencil may rotate in the direction of the arrow a or in a direction opposite thereto, and its axis of rotation is presented toward the grinding surface of the grinding wheel so that, if projected, it forms a chord to the circle of the abrading surface, or an angle to the axis of rotation of the grinding wheel, so that the abrading is accomplished by the end of the abrading pencil at one side of its axis of rotation, the abrading surface at the end of the abrading pencil being a substantial frusto-conical surface.

An electric motor 96 is provided and is instanced as comprising a casing 97 and an armature-shaft 98. The bearing barrel is outwardly flaring at its-end distanced from the abrading pencil, as shown by the flange 99, and forms the head of the motor-casing,

being secured to the latter by screws 101.

The armaturesluift is journaled in bearings 103 at the respective ends thereof, and is exemplified as flexibly connected with the shaft of the abrading pencil instanced as accomplished by providing a tooth-clutch 104 between the proximate ends of said shafts, the respective clutch-members being on said respective ends. (See ligs. 7, 8 and 9.) Thus the end of the armature-shaft is received in a socket 105 in the inner end ofthe socket being provided with slots 106, in which ends of a pin 107, secured in the'end of the armature-shaft, are received.

My improved device is such that a great saving in the durability of the grinding wheel is accomplished and effectiveness of the grindin wheel is enhanced, accomplished by the abrading pencil drawing or brushing the foreign'substances out of the recesses or pores in the grinding surface of the grinding wheel with a swirling motion, and presenting a device to the grinding wheel which eliminates the danger of gouging into the grinding surface. The extent of contact surface between the abrading pencil and the grinding wheel is relatively small, so that high speeds of rotation of the abrading pencil may be maintained with little expenditure of power, in order that the truing and dressing of the abrading wheel may be effective and economical and, if desired, take place during the grinding, in that the grinding wheel may be-causedto come in contact with the abrading pencil at each reciprocating movement of the grinding wheel.

In my improved construction, the abrading pencil and its support are relieved from vibrations of the motor and armature-shaft. The abrading pencil is held in fixed relation endwise, and the thrust of operation on the abrading is principally lengthwise of its axis, thereby insuring accuracy in the truing and dressing operation, and providing means whereby the grinding wheel is maintained in accurate condition.

Having thus fully described m invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a device for truing and dressing grinding wheels, the combination of a worksupport, rotating means thereon for rotating the work, a support for a grinding wheel, rotating means thereon for said grinding wheel, a rotatable abrading pencil mounted on said worksupport and arranged for coaction with said grinding wheel, means for rotating said rotatable abrading pencil, and means for causing movement between said supports lengthwise of the axes of rotation of said Work and said grinding wheel for selectively causing coaction between said rotatable grinding wheel and said rotatable work and between said rotatable abrading pencil and said rotatable grinding wheel while maintaining the axes of rotation of both said work and said grinding wheel at proper distance from each other for coaction between said grinding wheel and said work.

2. In a device for truing and dressing grinding wheels, the combination of a worksupport, rotating means thereon for rotating the work, a support for a grinding wheel, rotating means for said grinding wheel, a rotatable abrading pencil mounted on said work-support, rotating means for rotating said rotatable abrading pencil, and means for causing movement between said supports lengthwise of the axes of rotation of said grinding wheel for selectively causing coaction between said rotatable grinding wheel and said rotatable work and between said rotatable abrading pencil and said rotatable grinding wheel while the angular relations and distances between said axes of rotation are maintained 3. In a machine of the character described, the combination of a rotatable grinding wheel, means for supporting and rotating a piece of work, a rotatable abrading pencil having an axis of rotation presented toward said rotatable grinding wheel, and means for causing reciprocation between said rotatable abrading pencil and said rotatable grinding wheel and the work supported by said supporting means, to cause dressing action between said rotatable abrading pencil and said rotatable grinding wheel while ing relation between maintaining the grinding relation between said rotatable grinding wheel and said work.

4. In a machine of the character described, the combination of wheel, means for supporting and rotating a piece of work, a rotatable abrading pencil having a frusto-conical;end-abrading face, means for supporting said rotatable abrading pencil with relation to said rotatable grinding wheel to cause contact between said frusto-conical end-abrading face of said rotatable pencil, solely at one side of its axis of rotation, and said rotatable grinding wheel, and means for causing reciprocation between said rotatable grinding wheel and said rotatable abrading pencil and said work to cause dressing action between said rotatable abrading pencil and said rotatable grinding wheel while maintaining the grindsaid rotatable grinding wheel and said work.

5. In a machine of the character described, the combination of a rotatable grinding wheel, means for supporting and rotating a piece of work, a rotatable abrading pencil provided with a bore coincident with its axis of rotation and a frusto-conical end-abrading face surrounding said bore, means for a rotatable grinding supporting said rotatable abrading pencil with relation to said rotatable grinding wheel to cause contact between said frustoconical end-abrading face of said rotatable pencil and said rotatable grinding wheel solely at one side of said bore, and means for causing reciprocation between said rotatable grinding wheel and said rotatable abrading pencil and said work to cause dressing action between said rotatable abrading pencil and said rotatable grinding wheel while maintaining the grinding relation between said rotatable grinding wheel and said work.

6. In means for truing and dressing a grinding wheel, the combination with a grinding wheel, of means for supporting and rotating a piece of work, a rotatable abrading pencil of materially less diameter than the diameter of said grinding Wheel, means for positioning said abrading pencil with relation to said grinding wheel so as to present the axis of rotation of said abrading pencil toward the. grinding surface of said grinding wheel and cause abrading contact of the abrading surface of said abrading pencil with said grinding surface at one side abrading pencil, means for rotating said abrading pencil at materially greater speed of rotation than the speed of rotation of said grinding wheel, and means causing reciprocation with continuous movement between said rotatable grinding wheel and said rotatable abrading pencil and said work supported by said work-supporting means.

7. A rotatable abrading pencil of the character described having a bore coincident with its axis of rotation and a frusto-conical end-contact abrading face surrounding said bore, the radii of said frusto-conical endthrust abrading face being of greater lengths than the diameter of said bore.

In testimony whereof, I have hereunto signed my name in the presence of two subscribing witnesses.

EDWARD R. CONNERSJ WVitnesses:

I RALPH L. Hmns,

DELMA WERNSING.

only of the axis of rotation of said 

